package com.firefly.mobile.app.util;

import java.security.MessageDigest;

import javax.crypto.KeyGenerator;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

import android.util.Base64;
  
  
/**  
 * 基础加密组件  
 *   
 * @author ydw 
 * @version 1.0  
 * @since 1.0  
 */  
public abstract class Coder {   
    public static final String KEY_SHA = "SHA";   
    public static final String KEY_MD5 = "MD5";   
  
    /**  
     * MAC算法可选以下多种算法  
     *   
     * <pre>  
     * HmacMD5   
     * HmacSHA1   
     * HmacSHA256   
     * HmacSHA384   
     * HmacSHA512  
     * </pre>  
     */  
    public static final String KEY_MAC = "HmacMD5";   
  
    /**  
     * BASE64解密  
     *   
     * @param key  
     * @return  
     * @throws Exception  
     */  
    public static byte[] decryptBASE64(String key) throws Exception {   
        return Base64.decode(key, Base64.DEFAULT);   
    }   
  
    /**  
     * BASE64加密  
     *   
     * @param key  
     * @return  
     * @throws Exception  
     */  
    public static String encryptBASE64(byte[] key) throws Exception {   
        return Base64.encodeToString(key,Base64.DEFAULT);   
    }   
  
    /**  
     * MD5加密  
     *   
     * @param data  
     * @return  
     * @throws Exception  
     */  
    public static byte[] encryptMD5(byte[] data) throws Exception {   
  
        MessageDigest md5 = MessageDigest.getInstance(KEY_MD5);   
        md5.update(data);   
  
        return md5.digest();   
  
    }   
  
    /**  
     * SHA加密  
     *   
     * @param data  
     * @return  
     * @throws Exception  
     */  
    public static byte[] encryptSHA(byte[] data) throws Exception {   
  
        MessageDigest sha = MessageDigest.getInstance(KEY_SHA);   
        sha.update(data);   
  
        return sha.digest();   
  
    }   
  
    /**  
     * 初始化HMAC密钥  
     *   
     * @return  
     * @throws Exception  
     */  
    public static String initMacKey() throws Exception {   
        KeyGenerator keyGenerator = KeyGenerator.getInstance(KEY_MAC);   
  
        SecretKey secretKey = keyGenerator.generateKey();   
        return encryptBASE64(secretKey.getEncoded());   
    }   
  
    /**  
     * HMAC加密  
     *   
     * @param data  
     * @param key  
     * @return  
     * @throws Exception  
     */  
    public static byte[] encryptHMAC(byte[] data, String key) throws Exception {   
  
        SecretKey secretKey = new SecretKeySpec(decryptBASE64(key), KEY_MAC);   
        Mac mac = Mac.getInstance(secretKey.getAlgorithm());   
        mac.init(secretKey);   
  
        return mac.doFinal(data);   
  
    }   
}  
